[CMake] Fixing a small hack in add_lldb_library

This code was adding an explicit dependency on libclang because lldb needs clang headers, changing this to instead depend on the clang tablegen targets means we don't have to depend on building the clang bits in libclang that lldb doesn't need.

Note this is still a bit of a hack because we're adding the dependency to all lldb libraries, instead of just the ones that need it.

llvm-svn: 282196

Author: Chris Bieneman

lldb/cmake/modules/AddLLDB.cmake

@@ -91,7 +91,10 @@ macro(add_lldb_library name)
   # Hack: only some LLDB libraries depend on the clang autogenerated headers,
   # but it is simple enough to make all of LLDB depend on some of those
   # headers without negatively impacting much of anything.
-  add_dependencies(${name} libclang)
+  get_property(CLANG_TABLEGEN_TARGETS GLOBAL PROPERTY CLANG_TABLEGEN_TARGETS)
+  if(CLANG_TABLEGEN_TARGETS)
+    add_dependencies(${name} ${CLANG_TABLEGEN_TARGETS})
+  endif()
 
   set_target_properties(${name} PROPERTIES FOLDER "lldb libraries")
 endmacro(add_lldb_library)